Loss to follow-up: Understand its determinants among tuberculosis patients, in Coimbra District (2005-2017)

Tuberculosis patients who abscond from treatment are more likely to contribute to ongoing transmission. This growing concern has led to the development of this study in order to assess risk factors among Tuberculosis patients lost to follow up (LTFU) notified in the Coimbra District between 2005 and 2017.

A case-control study was designed to compare Tuberculosis patients LTFU (cases) to those successfully treated (controls). Forty-two LTFU cases were compared to 712 controls. Social and demographic data, co-morbidities, disease location, previous treatment history, drug resistance pattern and time period related to economic crisis were analyzed. In order to determine independent risk factors, numeric data was compared by one sample t-test; categorical data compared by the chi-square test or the fisher exact test, and included in a logistic regression analysis, in order to analyze their association to LTFU as a dependent variable.

Bivariate analysis found that LTFU patients were more likely to be immigrants (OR:2,54; 95%CI,1,36-4,75;p < 0,01); unemployed (OR:1,99; 95%CI, 1,08-3,69;p = 0,03); civil construction workers (OR:2,53; 95%CI,1,22-5,27;p = 0,01), have a history of drug (OR:3,29; 95%CI,1,57-6,91;p < 0,01), alcohol (OR:2,16; 95%CI,1,41-3,32; p < 0,01), and tobacco abuse (OR:1,60; 95%CI,1,12-2,30; p=0,02), HIV (OR:4,15; 95%CI,2,12-8,13; p < 0,01), Hepatitis C (OR:4,51; 95%CI,1,95-10,45; p < 0,01) and Hepatitis B (OR:12,97; 95%CI,3,00-56,02; p < 0,01) virus infection. Multivariate analysis found immigrants (aOR:3,08; 95% CI, 1,20-7,93; p = 0,02) and alcohol abuse (aOR:2,81; 95% CI, 1,22-6,47; p = 0,01) to be the strongest LTFU predictor.

LTFU likelihood was strongly associated to addictive behaviours and immigrants. It is important that the medical teams prioritize these patients for intensive follow-up care. It is recommended stronger coordination with other support services such as mental health and substance abuse programs. Multidrug-resistant tuberculosis makes necessary to highlight all of the strategies available to its prevention and management; those, should include legislative responses towards recalcitrant patients, particularly when all other less restrictive measures fail.